Wireless networks are becoming an increasingly popular means for the exchanging of voice and data between mobile nodes (such as cellular telephones, Personal Digital Assistants (PDAs), cellular telephone modems, and other devices). One example of a wireless network used for communication is the cellular wireless network. A user can seek information over the Internet or call anyone connected to the Public Switched Telephone Network (PSTN) from any place inside the coverage area of most wireless networks.
With the increase of the popularity of wireless applications, much of the network infrastructure has become over populated. Next generation networks are specifying call models that have mobile nodes always connected to the Internet. Even with no data traffic, the network may be expected to maintain an active connection for all users. One way to solve this problem may be to expand the infrastructure by installing more physical hardware to interconnect computers and users. Such equipment includes transmission media, satellites and antennas, routers, aggregators, repeaters, and other devices that control transmission paths. Another way to solve this problem may be to use code division multiple access (CDMA). CDMA permits multiple users on the same channel at the same time allowing the network infrastructure to support more wireless users.
CDMA may still be limited by the network infrastructure which needs to connect many users at one time. CDMA may use a mobile Internet Protocol (IP) which provides a mechanism for routing IP packets to mobile nodes that may be connected to any network while using their permanent IP address. Mobile IP can identify a host by a single IP address even while the mobile node physically moves its point of attachment from one network to another as in the case of a mobile user. A host, as described within, specifies a network that the mobile node may use to access other entities such as mobile nodes, other networks, or the Internet.
The mobile node may be able to discover whether it is at home or away from home. A mobile node is home or in a home area when the mobile node is in the cell sector defining the local boundaries of use of the mobile node. Routers acting as home agents (HAs) or foreign agents (FAs) may advertise their existence. HAs may be routers located on the mobile node's home network that are capable of tunneling (tunneling refers to packet re-addressing) the mobile node's packets to it while it is away. FAs may be routers on a foreign network that can de-tunnel these packets from the HA. Mobile IP allows for the delivery of IP packets to mobile nodes. This may allow for more users to be connected at one time, but mobile IP may still be limited by the network infrastructure capabilities.
Network routers may employ methods of routing signals to their destination that may optimize the availability of service during periods of excessive demand. A router may create or maintain a table of the available routes and their conditions and use this information along with distance and cost algorithms to determine the best route for a given packet.
A router may be used in a method for matching IP addresses to destination computers using an Address Resolution Protocol (ARP). ARP is a protocol that may be used for mapping an IP address to a physical machine address, or Media Access Control (MAC address), that may be recognized in the local network. A table, usually called the ARP cache, may be used to maintain a correlation between each MAC address and its corresponding IP address. The ARP cache is a place to store the MAC address and its corresponding IP address more or less temporarily. ARP provides the protocol rules for making this correlation between addresses and providing address conversion in both directions.
When an incoming data packet destined for a host machine on a particular local area network arrives at a router, the router makes an ARP request to find a physical host or MAC address that matches the IP address. ARP searches for a MAC address in the ARP cache and, if the ARP finds the matching MAC address, ARP provides the MAC address so that the data packet can be converted to the right packet length and format and sent to the machine. If no matching MAC address is found for the IP address, ARP broadcasts a request to all the machines on the Local Area Network (LAN) to determine if one machine knows that it has the specified IP address associated with it. A machine that recognizes the IP address as its own returns a reply so indicating. ARP updates the ARP cache for future reference and then sends the data packet to the MAC address that replied.
An ARP may be used in a routing system to optimally direct data packets to receiving nodes. Routing systems may be useful for allocating the hardware and software of the network infrastructure. CDMA third generation has the need for a network infrastructure to have the capability of supporting mobile nodes during periods of excessive demand for data connections, therefore, it may be useful to introduce a routing system to load balance mobile nodes to allow for a method of optimizing availability of service during periods of excess demand.